利用过滤器解决jsp乱码问题

import java.io.IOException;

import java.nio.charset.Charset;

import java.util.HashMap;

import java.util.Map;

import javax.servlet.Filter;

import javax.servlet.FilterChain;

import javax.servlet.FilterConfig;

import javax.servlet.ServletException;

import javax.servlet.ServletRequest;

import javax.servlet.ServletResponse;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletRequestWrapper;

public class GETCharacterEncodingFilter implements Filter{

private String charset = "UTF-8";

@Override

public void init(FilterConfig config) throws ServletException{

String temp = config.getInitParameter("charset"); //获取配置过滤器的charset参数对应的参数值

if (temp != null && !"".equals(temp.trim())) {

try {

this.charset = Charset.forName(temp).name(); //测试字符集是否存在

} catch (Exception e) {

this.charset = Charset.defaultCharset().name(); //如果字符集不存在在则使用当前JVM默认字符集

}

}

}

@Override

public void doFilter(ServletRequest req, ServletResponseresponse, FilterChain chain) throws IOException, ServletException{

HttpServletRequest request = (HttpServletRequest) req;

if ("get".equalsIgnoreCase(request.getMethod())) { //判断是否为get方式提交

request = new HttpServletRequestWrapper(request) { //重新包装request

@Override

public Map getParameterMap() {

Map map = super.getParameterMap(); // 原始的请求参数映射

Map temp = new HashMap(); // 编码后的请求参数映射

for (String key : map.keySet()) {

temp.put(key, this.getParameterValues(key));

}

return temp;

}

@Override

public String[] getParameterValues(String name) {

String[] values = super.getParameterValues(name); //根据name获取原始的参数值数组

String[] temp = new String[values.length]; // 编码后的参数值数组

for (int x = 0, y = values.length; x < y; x++) {

temp[x] = values[x] == null ? null : convert(values[x]);

}

return temp;

}

@Override

public String getParameter(String name) {

String value = super.getParameter(name);

return value == null ? null : convert(value);

}

private String convert(String value) { // 参数值重新编码

String temp = value.trim();

if ("".equals(temp)) {

return value;

}

try {

return new String(temp.getBytes("ISO8859-1"), charset);

} catch (Exception e) {

e.printStackTrace();

}

return value;

}

};

}

chain.doFilter(request, response);

}

@Override

public void destroy() {

}

}